Radio tuning apparatus



NOV. 30, 1937. D H, MBTQHELL ZLS RADo TUNING APPARATUS Filed June 24, 1935 5 Sheets-Sheet l NOV. 30, 1937. D. H MlTCHELL 2,101,009

RADIO TUNING APPARATUS Filed June 24, 1955 3 Sheets-Sheet 2 K Nov. 30, 1937. D. H, MITCHELL ZQLOGQ RADIO TUNING APPARATUS Filed June 24, 1935 5 Sheets-Sheet 3 L72 jjj 10g? X05 Patented Nov. 30, 1937 UNITED STATES PATENT OFFICE .RADIO TUNING APPARATUS Application June 24, 1935, Serial No. 28,037

12 Claims.

This invention relates to remote control apparatus and has been illustrated in combination with a radio receiving set. The invention is particularly suitable for use in automobiles or other vehicles in which the receiving set is mounted on the dashboard, and the control head is positioned on the instrument board, or the steering post, the connection between the two being partly mechanical. In some of its aspects the invention relates more broadly to control apparatus for radio receiving sets, even though it may be mounted directly on the cabinet or case of the set.

In the past there have been several forms of remote control apparatus of types suitable for the use described, but they have for the most part been unreliable, or expensive to manufacture, or troublesome in adjustment when installing the set. It is an important object of the present invention to provide remote control apparatus which may be attached to the radio set in a simple manner and without the necessity of accurate positioning of the chassis within its housing.

A related object is to provide a simple means of adjustment of the position of the axis of a gear on the chassis which is driven by a pinion forming a part of the control device and extending through the housing.

Another object of the invention is to provide a simple control device which requires a removable key to turn on the radio.

A further object is to provide means for easily and satisfactorily coupling the control device t0 the receiving set.

An additional object is to provide a simple and effective arrangement for mounting the dial light on the remote control head.

A further object is to provide a simple but delicately adjustable rheostat, and especially one which is suitable for use as a volume control unit in the remote control head; and

A still further object is to provide a coupling member for the flexible shaft to connect the shaft housing to the chassis housing in a positive mechanical and electrical connection.

Other objects and advantages of my invention will be apparent from the following description 0 taken with the drawings, in which:

Fig. l is a side elevation of a portion of a radio receiver set with part of the casing broken away to show interior portions thereof.

Fig. 2 is a fragmentary sectional view taken substantially along the line 2-2 of Fig. l.

Fig. 3 is a fragmentary sectional View taken substantially along the line 3-3 of Fig. 1.

Fig. 4 is a perspective view of the remote con-` trol apparatus chosen for illustration in this application.

Fig. 5 is an end View of one of the couplers as indicated by the line 5-5 of Fig. 4.

Fig. 6 is a fragmentary sectional View substantially along the line 6 6 of Fig. 4.

Fig. 7 is a corresponding fragmentary sectional View taken longitudinally along the station selector portion of this invention.

Fig. 8 is a fragmentary view illustrating one of the attachment holes in the casing of the set.

Fig. 9 is a perspective view showing the rear of the control head illustrated in Fig. 4.

Fig. 10 is a side View of the control head of Fig. 9 with a portion broken away to show a vertical section through the dial light assembly.

Fig. l1 is a fragmentary vertical sectional view through the rheostat used as a tone control unit.

Fig. 12 is a partially opened out view of the resistance unit in said rheostat.

Although this invention may take numerous` forms, only one has been chosen for illustration. 2

According to this form, a suitable housing Il is provided, in which may be located the chassis of a radio receiving set. The details of the receiving set need not be considered, for the most part, it being sufficient to state that it includes a switch and volume control element I2 such as a rheostat rigidly secured to the chassis and operated by a slotted stem I3; and one or more tuning condensers I4 or other tuning means controlled by a shaft I6. The condensers are all carried by a suitable frame II through the end plate of Which the shaft I6 extends. Mounted on the exposed end of the shaft I5 is a suitable gear segment I8 adapted to be turned by a pinion I9 through 1800 and having stops 2I for limiting the movement of the segment I8 to 180. Since the pinion I9 is supported at a deiinite position on the housing I I (in a manner described below) and since it is difcult in commercial production to always locate the chassis at exactly the same position in the housing, there has heretofore been difficulty in keeping the gears properly meshed. If they are too close they bind and if they are not close enough they permit play which is very undesirable in tuning. To overcome this difliculty, I provide means for adjusting the spacing of the gears by adjusting the position of the frame I l. This frame I'I is preferably pivotally mounted as by means of bolts 22 carried by upstanding brackets 23 rigidly secured to the frame of the chassis. The frame I1 is urged toward the pinion I9 by a spring 24, and its movement is limited byY an eccentric 26 pivotally secured to the frame I1 as by bolt 21. The bolt 21 may be Y screwed into nut 39, tightened until the eccentric 26 may be turned only with difficulty, and s01- dered to the nut to prevent loosening. The eccentric Z6 bears against any suitable stop, such as the inner wall of a rectangular hole in a bracket 28 mounted rigidly on the chassis. Thus it is seen that turning the eccentric 26 adjusts the position of the frame I1 and consequently of the segment I8 with respect to the pinion I9 which is separately supported, thereby assuring proper spacing of the segment I8 and the pinion I9 to permit smooth operation thereof.

The pinion I9 is carried rigidly on the end of a exible cable 3l which extends through a hole 29 in casing II and through a flexible tube or sheath 32 to the remote control head;

Rigidly or frictionally securedv on the end of the flexible sheathing 32 is a coupler 33 having a flat annular face 34 adapted to rest against the housing II of the set. Extending through the hole 29 is the nose 36 of the coupler 33. This nose is provided with two or more lugs 31 spaced from the face 34 and extending radially, as illustratedQ The hole 29 is provided with radially extending slots 38 through which the lugs 31 may pass. The arcuate portions 39 of the casing adjacent the slots 38 are cam-shapedV so that, as the coupler 33 is twisted after the lugs 31 are inserted through the slots 38, the lugs 31 ride up onto the cam portions 39 and draw the face 35 of coupler 33 tight against the housing II, This secures the coupler 33 quite rigidly to the Wall of the housing II and, since the pinion I9 is relatively rmly, though rotatably, held by the coupler 33, no further supporting of the pinion I9 is necessary. The housing II should be scraped clean where the coupler contacts it so that the sheathing will be well'grounded to the housing.

The pinion I9 is held properly positioned longitudinally with respect to the coupler 33 by any suitable means, as by a wire 4I passing between and interlocking with the lugs 31 and the pinion I 9. The interlocking is secured by means of grooves 42 formed on the inner sides 0f the lugs 31 and an annular groove 43 formed on the pinion I9 in a position to register with the groove 42. The two registering grooves form a channel only slightly larger than the wire 4I. The wire 4I may also serve as a bearing for the pinion, although the shank of the pinion preferably ts so well in the coupler 33 that the wire 4I is not necessary as a bearing. 'Ihe wire 4I may be a substantially U-shaped wire having its ends bent over, as at 44, to secure it in place. It will be understood, of course, that in applying this wire a long piece of wire may be threaded between the pinion I9 and one of the lugs 31 and back between the pinion and the other lug 31, drawn tight, bent over and cut off; or it may be a properly sized U-shaped wire slipped through both openings Vat once and bent over at both ends.

The pinion I9 maybe secured to the flexible cable 3l in any suitable manner, as by welding or crimping. Relative rotation between the two members is preferablyT prevented by flattening the sides of the pinion, as at 46, and the corresponding sides of the cable, as at 41, the cable being telescoped within the end of the pinion.

The flexible sheathing 32 passes into a suitable sleeve 49 or other opening in the casing or shell 5I of the control head and is secured irmly in place therein, as by a set screw 52. This not only assures proper operation of the cable, but also grounds the control head to the housing. Of course, it will usually be grounded also through the member on which it is supported. The flexible cable 3l projects from the end of the sheathing 32 and is rigidly secured to a handle 53 in any suitable manner, as by one or more set screws 54. The handle 53 is rotatably held in place by a set screw 5S which is mounted in the control head casing 5I and slidably engages an annular groove 55 in a. shank of the handle 53. rihus it is seen that the handle 53 turns the flexible cable 3| which turns the pinion I9 which meshes with the gear segment I8 and therefore slowly revolves movable portions of the tuning condensers E3.

In order to indicate the position of the condensers and therefore the radio frequency to which the receiving set is tuned, suitable indicating means is provided in the head. In the illustrated form this comprises a disc 51 having' painted or formed thereon a needle 58 which points to suitable markings arranged concentrically with the axis of the disc 51. The disc 51 may be secured rigidly to a stud 59 having an enlarged head 6I against which rests a gear 32 being urged thereagainst by a spring clip 63 engaging a slot in the stud 53. The head 5I may rotate in a suitable hole in the shell 5 i. The gear 62 may be in mesh with the smaller gear 64 of an intermediate gear set supported as by a stud B6, cold-pressed into a hole in the casing of the head, or otherwise secured therein. A large gear 61 is rigidly secured to the small gear 34 and meshes with gear teeth formed on the shank 38 of handle 53.

From the foregoing it is seen that as the handle 53 adjusts the condensers it also rotates the gears 61, G5. and 62 Vand thereby turns the indicator disc 51 to cause the needle 53 to move a distance corresponding to the movement of the condensers. When the receiving set is tuned to a broadcasting station of known frequency the indicating disc 51 may be rotated independently of the gearing to point to the number corresponding to'said frequency. To facilitate this initial setting of the disc 51 the head 5I is provided with a slot for a screw driver, as shown. The movement of the disc 51 independent of the gearing is permitted by the fact that the clip 51 comprises a friction clutch, since it clamps the gear 32 against the head 6I, the stud 59 and gear 32 being relatively rotatable except for the friction thus produced.

The indicating numbers may be formed in any desired manner, one preferred form being that they are indented on the back side of a plate of glass 1l, the indentations preferably being painted with a light paint to make them show up more clearly. An annular disc 12 of a blackened metal may be provided for supporting the glass 1l and for furnishing an optical contrast with the markings thereon. A crystal 13 of a no-n-breakable transparent material, will usually be provided for the sake of appearance and protection. The glass plate 1i may be held in position by a narrow ring of metal 1li which in turn isheld in place by the crystal 13, the latter being held in place as by a ring 15 pressed into the casing of the head.

To illuminate the figures an electric light bulb 1S is provided, which may be screwed into a socket 11 rigidly carried by a disc 13 which frictionally engages and electrically contacts a cup 'I9 having slots 8| along most of its length to make its open end resilient. The center terminal of the socket extends through and is insulated from the disc I8 and is connected to a wire 82 insulated as by a specially shaped rubber bushing 89, as illustrated. In assembly, one end of the wire 82, with the disc and socket attached to the other end, is threaded through the cup 19 (and through the bushing 83), and the disc and socket are drawn into the cup where they are held by the friction of the disc on the cup.

The cup 'I9 may be telescoped over and frictionally held on a rearwardly extending sleeve 84 formed on the shell 5| of the control head, the lamp 'I6 simultaneously being telescoped within the sleeve 84 to the position indicated by the dotted lines. Thus it is seen that the Whole lamp assembly is put together by simple operations without special securing means. From the lamp in its inner position light may pass, either directly or by reflection, through a slot 86 in annular disc I2 and into the glass plate 'II to illuminate the numbers formed thereon.

The needle 58 or the tip thereof may be specially illuminated by a slit cut through the disc 5l' and closed by a translucent member, as a piece of paper on the back, which will be caused to glow brightly by reflected light from the bulb 79. The brightness of the glowing portion of the arrow 58 may be increased by white or other light-reflecting paint on the inside surface of the casing of the control head, especially at the upper portion thereof. It should be understood, of course. that the lamp 'I6 will be controlled through the wire 82 in any suitable manner, usually by a switch which causes the lamp to light when the set is turned on.

The switch and volume control rheostat I2 of the set is operated by a slotted stem I3, as previously described. This slotted stem is engaged by a key 9i shown best in Fig. 6. This key is rigidly secured to the end of a flexible cable 92 in the same manner as the pinion I9 is secured on the cable 3|. Cable 92 is provided with a iexible sheathing 32 having fixed at its end a coupler S3, as described in connection with the cable 3l. The other end of the sheathing 32 is secured in the control head, as by a set screw 52 which is really in the position shown in Fig. 4 rather than that shown diagrammatically in Fig. 6. Secured to the control head end of the flexible cable 92 is a pinion 94 which extends into handle 9B, which is preferably freely rotatable with respect to the pinion 94, being rotatably held in the casing of the control head by a set screw 53.

It is preferred that the handle 96 be rotatable with respect to the pinion 94 to prevent the receiving set beng turned on by meddlers. To turn it on when desired, a removable key 91 is provided which extends through a slot in the end of handle 96 and engages the pinion 94. Turning the key 91, either directly or by means of the handle SS, will then turn the pinion 94, the cable @2, the key 9| and by it the stud I3 operating the receiving set switch and volume control rheostat I2.

In inserting the key 9| in the receiving set, it may first be drawn out by the amount of play between the sheathing 32 and the inner end of the shank of pinion 94. This makes it easy to manipulate the key 9| to cause it to engage the slot in slotted stem I3 after which time the associated coupler 33 may be inserted through the case of the set and turned to a locked position,

as described in connection with pinion I9. Thrusting the coupler 33 through the casing has the effect of pushing the key 9| relatively into the coupler 33 and therefore pushing the pinion 94 to its original position, as shown in Fig. 6.

A tone control wire IGI extends from the receiving set to the control head. Since the circuits with which it is connected may be conventional and are not considered a part of the invention covered by this application, they need not be described. It is sufcient to explain that, if the wire IBI is grounded to the metal frame of the car, as through the casing of the control head, the tone of the sound issuing from the loud speaker of the set is altered and, if a variable resistance or rheostat is inserted between the Wire IGI and the ground, the tone may be varied at will. To this end a resistance block |92 of a suitable material, such as carbon, is placed in a recess in the control head shell 5| and thoroughly insulated from said shell as by a wrapping |03 of insulating paper and an insulating washer I 04 at its inner end. Engaging the outer end of the resistance block |92 is a spring contact member |96 insulated from and carried by a screw cap I9?. The wire IIJI extends through the cup |01 to the contact I (I6, being insulated from the screw cap by a rubber bushing |08 and by the disc |09 of insulating material which carries the contact IDB, Screwed into the front of the casing of the control head is a stud III having a handle II2. Formed on the inner end of the stud III is a bifurcated Contact member, the prongs I|3 of which are resiliently urged outwardly and normally extend into a central bore in the block |92 "i and engage the sides thereof. When the stud III is screwed all the way in, the tips of the prongs II3 engage the spring contact I 06 and connect the wire IDI to ground substantially Without resistance. As the stud III is screwed outwardly the resistance |02 is placed in the circuit, thereby varying the control. As the stud I I I is screwed outwardly, the resistance increases until, when the bifurcated contact member I|3 passes out of contact with the resistance block |92, the circuit is completely broken.

Suitable spring jacks are provided within the case of the receiving set for connection with the wires I 0| and 82. To make contact with these spring jacks, plugs or connectors are provided, including tips IIB which are preferably soldered to the respective wires and may have handles I Il of insulation secured thereto to facilitate insertion and removal and to protect the wires. In forming these plugs hollow metal tips I IS having annular shoulders I I8 crimped thereon are slipped into the insulator I II which may previously have had an inwardly extending flange formed on its engaging end. The end of the tip I I6 within the insulator I I? is then upset to hold the insulator in place. In the same operation the insulator may be flared at its free end.

I claim:

l. In a radio receiving set, a housing, a chassis removably located in said housing and including spaced brackets, a frame pivoted to said brackets, at least one tuning condenser carried by said frame and including a rotatably mounted shaft, a gear carried by said shaft and fixed thereon, a pinion rotatably mounted on said housing for driving said gear, a spring urging said frame and gear toward said pinion, and means adjustable after said chassis is in said housing for limiting said movement, whereby free CTI driving action of said gear by said pinion Without play may be obtained. Y

2. In a radio receivingset, a housing, a chassis removably located in said housing and including spaced brackets, a frame pivoted to said brackets, at least one tuning condenser carried by said frame and including a rotatably mounted shaft, a gear carried by said shaft and xed thereon, a pinion rotatably mounted on said housing for driving said gear, a` spring urging said frame and gear toward said pinion, and adjustable means for limiting said movement, whereby free driving action of said gear by said pinion without play may be obtained.

3. In a radio receiving set, a housing, a chassis removably located in said housing and including spaced brackets, a frame pivoted to said brackets, at least one tuning condenser Vcarried by said frame and including a rotatably mounted shaft, a gear carried'by said shaft and fixed thereon, a pinion rotatably mounted on said housing for driving said gear, and a spring urging said frame and gear toward said pinion.

4. In a radio receiving set, a housing, a chassis removably located in said housing and including spaced brackets, a frame pivoted to said brackets, at least one tuning condenser carried by said frame and including a rotatably mounted shaft, a gear carried by said shaft and fixed'thereon, a pinion rotatably mounted on said housing for driving said gear, and means adjustable after said chassis is in said housing for pivoting said Vframe to position said gear a proper distance from said pinion.

5. In a radio receiving set, a housing, a chassis removably located within said housing, a tuning condenser on said chassis including a rotatably mounted shaft, a gear mounted on said shaft for rotating said tuning condenser, a pinion rotatably mounted on said housing and meshing with said gear, and means accessible from. the outside of the housing for adjusting one of said meshing members with respect to its support means to properly space said meshing members with respect to one another in spite of variations in the position of said chassis within said housing.

6. In a radio receiving set, a housing having a control pinion rotatably mounted thereon with a portion extending therethrough, a radio chassis 'removably secured within said housing and including a main portion and support means pivoted thereto, a control element rotatably mounted on said support m-Ieans, a toothed operating member mounted on said control element and engaging said pinion, and means for pivoting said pivoted support means torproperly space said pinion and said operating member so that the two will properly mesh in spite of variations in the relative position of the chassis within the housing.

7. In a radio receiving set, a housing having a control pinion rotatably mounted thereon with a portion extending therethrough, a radio chassis removably secured Within said housing and including a main portion and support means. pivoted thereto, a control element rotatably mounted on said support means, Ya toothed operating member mounted on said control element and engaging said pinion, and means adjustable from the outside of the housing for properly positioning said pivoted support means to properly space said pinion and said operating member so that the two will properly mesh in spite of variations in the relative position of the chassis within the housing, said positioning means including resilient means for urging said controlling member toward said pinion and an adjustable stop device for limiting its movement toward said pinion.

8. In a radio receiving set, a housing having a control pinion rotatably mounted thereon with a portion extending therethrough, a chassis removably secured within said housing and including pivoted support means, a control element rotatably mounted on said support means, a toothed operating member mounted on said control element and engaging said pinion, and means for properly positioning said pivoted support means to properly space said pinion and said operating member so that the two will properly mesh in spite of variations in the relative position of the chassis within the housing, said positioning means including resilient means for urging said controlling means toward said pinion and an adjustable stop devicefor limiting its movement toward said pinion, said adjustable stop device comprising -an eccentric rotatably mounted on one of the relatively movable members and a stop engaged by said eccentric, said housing having a hole positioned to give access to said eccentric for the adjustment thereof through said case.

9. The combination of a radio receiver having a chassis with a receiver circuit and receiver elements thereon, including control elements in the receiver circuit, a housing for said receiver chassis and remote control means for adjustably operating said control elements, said remote control means including a control head having flexible cables extending therefrom and corresponding in number to the control elements on said receiver chassis, with one of said flexible cables including a flexible conduit fixedly secured on said control head and extending to a housing coupling at the other end xed thereon, and a flexible shaft in said conduit, connecting means on each end of said shaft, one of said connecting means rotatable at the control head and the other of said connecting means rotating at the coupling, with said flexible shaft and connecting means longer than said conduit, and longitudinally aswell as rotatably movable therein, with each of said connecting means having a shoulder thereon cooperating at the control head and at the coupling to limit the longitudinal movement of the exible cable in the conduit, said coupling on the end of said conduit having a pair of slotted lugs thereon for mounting the coupling in a corresponding aperture in said housing adjacent a control element, with the slots in the lugs receiving the edge of said aperture tolock said coupling on said housing, with said length of each of said flexible shafts providing a lost motion between said control head and said conduit upon connecting and disconnecting said coupling at the housing, whereby the connecting means on the end of the shaft may be partially Withdrawn with the shaft from said conduit to be inserted into proper position in a control element before said coupling is connected to said housing, such withdrawing movement of said flexible shaft being limited by the shoulder on the connecting means at the control head'end of said shaft.

10. In a radio receiving set, a housing, a control element within said housing, a handle on the outside of said housing, a toothed member rotatable within said handle and normally connected in driving relation to said control element, and a key having its front end bifurcated and shaped to engage therteeth on said toothed member, said handle being slotted to receive said key without permitting its rotation with respect to said handle whereby, when said key is in place, said handle is in driving relation with said toothed member.

11. In a radio receiving set, a housing, a control element Within said housing, a handle on the outside of said housing, a toothed member rotatable Within said handle and normally connected in driving relation to said control element, and a key having its front end bifurcated and shaped to engage the teeth on said toothed member, said handle being slotted to receive said key without permitting its rotation with respect to said handle whereby, when said key is in place, said handle is in driving relation with said toothed member, a means for retaining said key in place comprising a resilient split ring positioned in an annular groove on the outside of said handle, said key having notched sides which extend into said groove except when the notches therein register with said groove.

12. In a radio receiving set, a housing, a receiver chassis removably located Within said housing and substantially xed with respect to said housing in said located position, a tuning condenser mounted on said chassis, including a rotatably mounted shaft having a gear thereon for rotating said tuning condenser, a driving pinion meshing with said gear, means fixed with respect to said housing for rotatably mounting said pinion on said housing, and adjusting means accessible from the outside of said housing for moving said condenser with respect to said chassis to properly space said meshing members With respect to one another irrespective of variations in the located position of said chassis within said housing.

DONALD H. MITCHELL. 

